Well, for the last 5 years or so I've been wanting to design and implement my own computer processor. I've finally got something working, and I'm ready to share it with the world! I'm releasing the vhdl source here, along with the ModelSim project I made it with.
I've also got some simulation and code generation software available here.

VHDL source

I'm also going to post some of the documents I generated while designing this mess.

ISA Specification
Component Tests